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Title: Size-tunable Lateral Confinement in Monolayer Semiconductors

Abstract

Three-dimensional confinement allows semiconductor quantum dots to exhibit size-tunable electronic and optical properties that enable a wide range of opto-electronic applications from displays, solar cells and bio-medical imaging to single-electron devices. Additional modalities such as spin and valley properties in monolayer transition metal dichalcogenides provide further degrees of freedom requisite for information processing and spintronics. In nanostructures, however, spatial confinement can cause hybridization that inhibits the robustness of these emergent properties. Here in this paper, we show that laterally-confined excitons in monolayer MoS 2 nanodots can be created through top-down nanopatterning with controlled size tunability. Unlike chemically-exfoliated monolayer nanoparticles, the lithographically patterned monolayer semiconductor nanodots down to a radius of 15 nm exhibit the same valley polarization as in a continuous monolayer sheet. The inherited bulk spin and valley properties, the size dependence of excitonic energies, and the ability to fabricate MoS 2 nanostructures using semiconductor-compatible processing suggest that monolayer semiconductor nanodots have potential to be multimodal building blocks of integrated optoelectronics and spintronics systems

Authors:
 [1];  [2];  [3];  [3];  [2]; ORCiD logo [4]
  1. Northwestern Univ., Evanston, IL (United States). Applied Physics Program
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
  3. Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy
  4. Northwestern Univ., Evanston, IL (United States). Applied Physics Program; Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
OSTI Identifier:
1420072
Grant/Contract Number:
AC02-06CH11357; SC0012130
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; Electronic properties and materials; Nanoparticles; Quantum dots; Two-dimensional materials

Citation Formats

Wei, Guohua, Czaplewski, David A., Lenferink, Erik J., Stanev, Teodor K., Jung, Il Woong, and Stern, Nathaniel P. Size-tunable Lateral Confinement in Monolayer Semiconductors. United States: N. p., 2017. Web. doi:10.1038/s41598-017-03594-z.
Wei, Guohua, Czaplewski, David A., Lenferink, Erik J., Stanev, Teodor K., Jung, Il Woong, & Stern, Nathaniel P. Size-tunable Lateral Confinement in Monolayer Semiconductors. United States. doi:10.1038/s41598-017-03594-z.
Wei, Guohua, Czaplewski, David A., Lenferink, Erik J., Stanev, Teodor K., Jung, Il Woong, and Stern, Nathaniel P. Mon . "Size-tunable Lateral Confinement in Monolayer Semiconductors". United States. doi:10.1038/s41598-017-03594-z. https://www.osti.gov/servlets/purl/1420072.
@article{osti_1420072,
title = {Size-tunable Lateral Confinement in Monolayer Semiconductors},
author = {Wei, Guohua and Czaplewski, David A. and Lenferink, Erik J. and Stanev, Teodor K. and Jung, Il Woong and Stern, Nathaniel P.},
abstractNote = {Three-dimensional confinement allows semiconductor quantum dots to exhibit size-tunable electronic and optical properties that enable a wide range of opto-electronic applications from displays, solar cells and bio-medical imaging to single-electron devices. Additional modalities such as spin and valley properties in monolayer transition metal dichalcogenides provide further degrees of freedom requisite for information processing and spintronics. In nanostructures, however, spatial confinement can cause hybridization that inhibits the robustness of these emergent properties. Here in this paper, we show that laterally-confined excitons in monolayer MoS2 nanodots can be created through top-down nanopatterning with controlled size tunability. Unlike chemically-exfoliated monolayer nanoparticles, the lithographically patterned monolayer semiconductor nanodots down to a radius of 15 nm exhibit the same valley polarization as in a continuous monolayer sheet. The inherited bulk spin and valley properties, the size dependence of excitonic energies, and the ability to fabricate MoS2 nanostructures using semiconductor-compatible processing suggest that monolayer semiconductor nanodots have potential to be multimodal building blocks of integrated optoelectronics and spintronics systems},
doi = {10.1038/s41598-017-03594-z},
journal = {Scientific Reports},
number = 1,
volume = 7,
place = {United States},
year = {Mon Jun 12 00:00:00 EDT 2017},
month = {Mon Jun 12 00:00:00 EDT 2017}
}

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Cited by: 3works
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  • The formation of semiconductor heterojunctions and their high density integration are foundations of modern electronics and optoelectronics. To enable two-dimensional (2D) crystalline semiconductors as building blocks in next generation electronics, developing methods to deterministically form lateral heterojunctions is crucial. Here we demonstrate a process strategy for the formation of lithographically-patterned lateral semiconducting heterojunctions within a single 2D crystal. E-beam lithography is used to pattern MoSe 2 monolayer crystals with SiO 2, and the exposed locations are selectively and totally converted to MoS 2 using pulsed laser deposition (PLD) of sulfur in order to form MoSe 2/MoS 2 heterojunctions in predefinedmore » patterns. The junctions and conversion process are characterized by atomically resolved scanning transmission electron microscopy, photoluminescence, and Raman spectroscopy. This demonstration of lateral semiconductor heterojunction arrays within a single 2D crystal is an essential step for the lateral integration of 2D semiconductor building blocks with different electronic and optoelectronic properties for high-density, ultrathin circuitry.« less
  • Lateral charge transport in a redox)active monolayer can be utilized for solar energy harvesting. We chose the porphyrin system to study the influence of the solvent on lateral hole hopping, which plays a crucial role in the charge)transfer kinetics. We also examined the influence of water, acetonitrile, and propylene carbonate as solvents. Hole)hopping lifetimes varied by nearly three orders of magnitude among solvents, ranging from 3 ns in water to 2800 ns in propylene carbonate, and increased nonlinearly as a function of added acetonitrile in aqueous solvent mixtures. Our results elucidate the important roles of solvation, molecular packing dynamics, andmore » lateral charge)transfer mechanisms that have implications for all dye)sensitized photoelectrochemical device designs.« less
  • Lateral charge transport in a redox)active monolayer can be utilized for solar energy harvesting. We chose the porphyrin system to study the influence of the solvent on lateral hole hopping, which plays a crucial role in the charge)transfer kinetics. We also examined the influence of water, acetonitrile, and propylene carbonate as solvents. Hole)hopping lifetimes varied by nearly three orders of magnitude among solvents, ranging from 3 ns in water to 2800 ns in propylene carbonate, and increased nonlinearly as a function of added acetonitrile in aqueous solvent mixtures. Our results elucidate the important roles of solvation, molecular packing dynamics, andmore » lateral charge)transfer mechanisms that have implications for all dye)sensitized photoelectrochemical device designs.« less
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